Fusarium verticillioides contamination patterns in Northern Italian maize during the growing season

caused by F. verticillioides may reduce crop yield. Fumonisins produced by the fungus may harm humans and animals. In order to gather information on contamination patterns of F. verticillioides under field conditions, the current study assessed the isolation frequency percentages (IFs) of the fungus during different growth stages (GS) of four maize hybrids (Arma, Costanza, Kubrick and Tucson) cultivated in Northern Italy. Fusarium verticillioides contamination was detected in all the examined plants and in maize crop residues, but IF levels varied depending on the GS. The fungus colonized all the residues of maize plant organs, and ear debris were the preferential survival sites. Fusarium verticillioides was the major fungal contaminant at GS 00, in all seed lots with the only exception of Tucson hybrid. At the seedling stage GS 13, a similar isolation pattern was observed, but with lower IFs than in the correspondent seedlings grown in aseptic conditions: roots and mesocotyls were more contaminated than leaves. In plants before silking (GS 53), F. verticillioides contamination was localized in the basal organs. At maturity (GS 89), however, a general increase of IFs was observed in all organs. Since glumes and husks were the most contaminated organs, silks can be considered the most important pathways for F. verticillioides infection. The present study analyzes the endemic presence of F. verticillioides in Northern Italian fields and suggests further research of resistance factors in silks and husks as to indicate possible mechanisms for reducing fungal contamination

A polyphasic approach for the characterization of endophytic Alternaria strains isolated from grapevines

A polyphasic approach was set up and applied to characterize 20 fungal endophytes belonging to the genus Alternaria, recovered from grapevine in different Italian regions. Morphological, microscopical, molecular and chemical investigations were performed and the obtained results were combined in a pooled cluster analysis. Following morphological analyses, all strains were grouped according to their three-dimensional sporulation pattern on PCA and to the colony characteristics on different substrates. After DNA extraction, all strains were analyzed by RAPD-PCR and the resulting profiles were subjected to cluster analysis. The metabolites extracted from the 20 Alternaria endophytes were analyzed by a HPLC and the resulting metabolite profiles were subjected to multivariate statistic analyses. In comparison with reference \u2018small-spored\u2019 Alternaria species, the 20 strains were segregated into two morphological groups: one belonging to the A. arborescens species-group and a second to the A. tenuissima species-group. RAPD analysis also showed that grapevine endophytes belonged to either the A. arborescens or the A. tenuissima species-group and that they were molecularly distinct from strains belonging to A. alternata. Chemotaxonomy gave the same grouping: the grapevine endophytic strains belong to A. arborescens or A. tenuissima speciesgroups producing known metabolites typical of these species-groups. Interestingly, the 20 grapevine endophytes were able to produce also a number of unknownmetabolites,whose characterization could be useful for amore precise segregation of the two species-groups. The results show how complementary morphological, molecular and chemical data can clarify relationships among endophyte species-groups of low morphological divergence